Salisbury district hospital’s A&E department was closed for a time as a result of the incident.
Photograph: Alamy

Two people are critically ill after being exposed to an unknown substance in an incident that is being investigated by government experts in chemical hazards and radiation.

An area of Salisbury city centre and part of the city’s district hospital were decontaminated but Public Health England said it did not believe there was a wider risk to the public.

The incident began on Sunday afternoon when police received a call that a man and woman had been taken ill in the Maltings shopping centre in Salisbury. The woman, who was unconscious, was airlifted to Salisbury district hospital and the man taken there by road.

Officers cordoned off an area around a bench where one of the pair had vomited. Firefighters in specialist suits then decontaminated it. The material they removed from the scene was wrapped in protective layers and was and removed.

On Monday morning a major incident was declared. Firefighters and police were seen at the hospital.

A patient who attended the accident and emergency department at the time said the incident caused “chaos”.

The man, in his mid-20s who did not want to be named, said he had been taken to a boardroom in the hospital while the fire service decontaminated the scene.

He said: “The staff said something to me about chemicals and that it had all happened in front of the A&E entrance.

“It caused chaos inside the A&E department. I was taken to a boardroom where I had to wait while they dealt with it.

“There was a green tent set up in the drop-off area and people in forensics clothes were all walking around.”

Wiltshire police said: “Police received a call at approximately 4.15pm … [on] 4 March regarding concern for the welfare of a man and a woman in the Maltings.

“It is not yet clear if a crime has been committed and a multi-agency response has been coordinated. Police are carrying out a full investigation and working with partner agencies to clarify the exact circumstances.”

A Public Health England spokesman said there did not appear to be any further immediate risk to public health.

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